This study was carried out to evaluate the value chain performance of the aquaculture feed sector in Egypt, in terms of value addition, employment and profitability. The strengths and weaknesses of each link of the value chain were assessed and appropriate upgrading, management and development strategies were suggested. Quantitative data were collected for each link in the value-chain through structured questionnaires that were drafted and distributed to the key players in the sector; 25 fish feed mills and 34 fish farms covering different geographical and production regions.
The introduction of Tilapia rendalli in Lake Sauce is described,outlining the various biological investigations which were necessaryfor management of the lake and biomass estimation, age determinationand overcrowding.
The current status of tilapia culture in Sudan is examined, describing the pond culture system used. Future prospects are also examined. It is believed that great effort is required before fish farming can boost food supply inthe country.
A brief account is given of project activities conducted regarding promotion of rice-cum-fish culture in Surin Province,Thailand as a means of increasing protein consumption and also income for rural people. The effect of stocking rate and stocking size on production was investigated. Three fish species were used: Cyprinus carpio, Puntius gonionotus and Oreochromis niloticus . It is believed that further research is warranted regarding rice-fish systems in which wild and cultured species can co-exist.
The development of a saline tolerant tilapia strain able to grow fast is of importance in the Philippines, where 240 000 ha of brackish water ponds are available. To this end, founder hybridization between Oreochromis niloticus (with favorable growth traits) and O. mossambicus (with favorable salinity tolerance traits) was performed and followed by backcrossing with O. mossambicus to develop a strain highly tolerant to saline environments. Genetic selection for growth performance was subsequently conducted.
The Abbassa selection line (developed by selective breeding) and the Kafr El Sheikh commercial strain (widely used in Egypt), both Oreochromis niloticus, were compared at two stocking densities (two and four fish m-2). Harvest weight, length, depth, width and head length were recorded. The Abbassa line showed a superior harvest weight (28 per cent) over the Kafr El Sheikh strain. Males were heavier than females, but the between-sex difference was greater in the commercial than in the Abbassa line (39 and 31 per cent respectively).
Econometric techniques were used to estimate a production function for tilapia pond culture in El-Fayum Governorate, Egypt, utilizing cross-sectional field data. Explanatory variables were feed, initial stocking weight, and pond size. The function was used to examine returns to scale, estimate the productivity of feed and initial stocking weight, and estimate the profit maximizing demand equations for feed and fingerlings. Diminishing returns to scale seem to exist for tilapia pond culture.
Polyculture of tilapias (Oreo¬chromis niloticus and 0. mossambicus/O. niloticus hybrid) with shrimp (Penaeus orientalis) has been investigated several times in China since 1981. The results have caused much debate. Oppositionists held that finfish, especially tilapias, would rapidly consume the shrimp postlarvae and juveniles as happened when shrimp were put together with tilapias in a small tank. This article gave an overview of this practice in China.
The effects of ditch size on growth and production of mono-sex tilapia, Oreochromis niloticus in rain fed concurrent rice–fish system were technically and economically evaluated for a period of 4 months. Three different ditch sizes were tried: 5%, 10% and 15% of the total cultivable rice field. It is concluded that rice–fish farming in a rain fed ecosystem of Bangladesh with medium ditch size and stocking density of 5000 ha-1 mono-sex tilapia can achieve better economic return.
Although it appears that the first recorded, scientifically oriented culture of tilapia was conducted in Kenya in 1924,of the current 30,000 ponds with a potential annual production of more than 7,000 tons, only 10% are functional producing 500 tons/annum. Tilapia tank culture at Baobab Farm is described in detail. The economics and prospectsof intensive culture in Kenya are considered.